1
GATE CSE 2016 Set 2
MCQ (Single Correct Answer)
+1
-0.3
$$N$$ items are stored in a sorted doubly linked list. For a $$delete$$ operation, a pointer is provided to the record to be deleted. For a $$decrease$$-$$key$$ operation, a pointer is provided to the record on which the operation is to be performed.

An algorithm performs the following operations on the list in this order:
$$\Theta \left( N \right),\,\,delete,\,\,O\left( {\log N} \right)\,insert,\,$$ $$\,O\left( {\log N} \right)\,fund, and $$ $$\Theta \left( N \right)\,$$ $$decrease$$-$$key.$$ What is the time complexity of all these operations put together?

A
$$O\left( {{{\log }^2}N} \right)$$
B
$$O\left( N \right)$$
C
$$O\left( {{N^2}} \right)$$
D
$$\Theta \left( {{N^2}\log N} \right)$$
2
GATE CSE 2016 Set 2
MCQ (Single Correct Answer)
+1
-0.3
Suppose a database schedule $$S$$ involves transactions $${T_1},\,...,\,{T_n}.$$ Construct the precedence graph of $$S$$ with vertices representing the transactions and edges representing the conflicts. If $$S$$ is serializable, which one of the following orderings of the vertices of the precedence graph is guaranteed to yield a serial schedule?
A
Topological order
B
Depth-first order
C
Breadth-first order
D
Ascending order of transaction indices
3
GATE CSE 2016 Set 2
MCQ (Single Correct Answer)
+2
-0.6
Consider the following database schedule with two transactions, T1 and T2
 S = r2(X); r1(X); r2(Y); w1(X); r1(Y); w2(X); a1; a2

where ri(Z) denotes a read operation by transaction Ti on a variable Z, wi(Z) denotes a write operation by Ti on a variable Z and ai denotes an abort by transaction Ti .

Which one of the following statements about the above schedule is TRUE?

A
S is non-recoverable
B
S is recoverable, but has a cascading abort
C
S does not have a cascading abort
D
S is strict
4
GATE CSE 2016 Set 2
Numerical
+2
-0
Consider the following database table named $$water$$_$$schemes :$$

water_schemes
scheme_no district_name capacity
1 Ajmer 20
1 Bikaner 10
2 Bikaner 10
3 Bikaner 20
1 Churu 10
2 Churu 20
1 Dungargarh 10

The number of tuples returned by the following $$SQL$$ query is _______________.

with total(name, capacity) as
    select district_name, sum(capacity)
    from water_schemes
    group by district_name
with total_avg(capacity) as
    select avg(capacity)
    from total
select name
    from total, total_avg
    where total.capacity ≥ total_avg.capacity
Your input ____
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